Enhanced Third-Order Nonlinear Optical Properties through Covalent Interfacial Interactions in Defective COF@CNT.
Jing Du1, Yi Wei1, Kangshuai Geng1
1College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, P. R. China.
Inorganic Chemistry
|April 22, 2026
Summary
Defect engineering in covalent organic frameworks (COFs) integrated with carbon nanotubes (CNTs) significantly enhances third-order nonlinear optical (NLO) properties. This novel composite material shows improved performance for advanced NLO applications.
Area of Science:
- Materials Science
- Optics
- Nanotechnology
Background:
- Third-order nonlinear optical (NLO) materials are crucial for advanced photonic applications.
- Achieving favorable interfacial compatibility in composite materials is key to enhancing NLO performance.
- Defect engineering offers a promising strategy to tune material properties.
Purpose of the Study:
- To develop novel composite materials with enhanced third-order NLO properties.
- To investigate the role of defect engineering in improving interfacial compatibility and NLO performance.
- To explore the potential of defective covalent organic framework/carbon nanotube composites (d-COF@CNT) for NLO applications.
Main Methods:
- Synthesis of defective covalent organic frameworks (d-COFs) using 1,3,5-triformylphloroglucinol (Tp) and diamines, modulated by R-/S-1-(1-naphthyl)ethylamine (R-/S-NEA).
- Integration of d-COFs with aminated carbon nanotubes (CNTs) to form d-COF@CNT composites.
- Characterization of NLO properties, including reverse saturation absorption (RSA) and self-focusing, under laser irradiation.
- Theoretical calculations and femtosecond transient absorption spectroscopy (fs-TAS) for mechanistic insights.
Main Results:
- The d-COF@CNT composites exhibited significantly enhanced third-order NLO performance in both near-infrared and visible ranges.
- Specific examples like d-Bpy-COF@CNT showed substantial improvements in RSA (3.16-fold at 1030 nm) and self-focusing (2.34-fold).
- Enhanced interfacial compatibility due to defect sites was identified as the primary factor for improved electron transfer and NLO properties.
Conclusions:
- Defect engineering in COF@CNT composites is an effective strategy to achieve superior third-order NLO performance.
- The enhanced interfacial compatibility plays a critical role in boosting electron transfer efficiency and NLO responses.
- This work provides a new pathway for designing advanced NLO materials for photonic devices.
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